The invention relates to a tool and more specifically to a compliant rotary powered tool that is gripped in the mechanical arms of a machine.
One of the applications for which the novel compliant rotary powered tool has been designed relates to offshore oil production platforms. These platforms require continual maintenance and inspection of their tubular structures that are anchored at water depths down at 1100 feet. At the junctions of these tubular structures, they form nodes of varying complexity.
The action of swells and ocean currents subject bracings to stress and strain resulting in metal fatigue and electrolysis results in corrosion of these welded joints. Therefore, it is important to make regular inspections to determine the condition of every weld in these junctions.
Present day inspection techniques require, first of all, fine cleaning to remove marine growth and oxides covering the welds. Inspection takes place after the bare metal of the welds is made visible. Divers routinely carry out this work using water jets and rotary brushes, but diving hazards and expenses increase rapidly with increasing water depths. To replace divers, there exist removably controlled mechanical means of cleaning nodes.
Up to now, they haven.times.t been very effective. Traditional manipulator arms are in fact, inappropriate for this type of cleaning since they lack the sense of feel or touch necessary for the effective control of standard driver tools. Because conventional remotely controlled manipulators are incapable of finely responding to small variations of force, they are incapable of maintaining appropriate contact force between a tool and a work surface. For the same reason, they are also incapable of accurately tracing a complex curve such as is found, for example, at the junction of a platform leg and a bracing member.
The prior art has not been able to produce a structure which would allow compact mechanical arms to be given feel or touch abilities such as humans have. The mechanical arms have merely been able to advance the power tools and their operating structures against the surface to be worked upon but oftentimes the force applied by the arm is either excessive or insufficient to accomplish the results desired of the power tools.
One example of apparatus that has been designed for cleaning weldments on offshore platforms is illustrated in U.S. Pat. No. 4,502,407. Millions of dollars have been spent on the research and development of this device yet it remains essentially ineffective due to the lack of a compliant rotary powered tool and the inability of its mechanical arms to apply a standard non-compliant tool effectively against a surface to be cleaned.
It is an object of the invention to provide a novel compliant rotary powered tool that can be utilized to clean weldments on offshore platforms.
It is also an object of the invention to provide a novel compliant rotary powered tool that can be carried by remotely operated vehicles (ROV's).
It is another object of the invention to provide a novel compliant rotary powered tool that allows undersea cleaning of weldments of offshore platforms to be done as effectively in the hands of mechanical arms as it would be done by human divers.
It is a further object of the invention to provide a novel compliant rotary powered tool that is economical to manufacture, market and maintain.